1. Field of the Invention
The present invention relates to a coupling system between an electromagnetic switch apparatus and an auxiliary contact block releasably mounted thereupon, the coupling system intended to actuate, by the agency of a catch projecting out of the casing of the switch apparatus and displaceable upon actuation of the switch apparatus, an auxiliary contact carrier slidingly supported in the auxiliary contact block and having a coupling member projecting out of said contact block.
2. Description of the Prior Art
A coupling system of the kind set forth above is disclosed in the German published patent application DE-OS No. 16 15 903. If the auxiliary contact block is removed, the catch of mentioned coupling system projects out of the casing of the switch apparatus. Projecting structures are, however, not desired. The catch itself is designed as a plunger which holds the auxiliary contact carrier in the OFF-position against the action of a force. If the switch apparatus is switched in, the plunger is pulled back into the casing of the switch apparatus and the auxiliary contact carrier follows this movement under action of a spring. The design of this system provides no positive coupling between the movements of the plunger and of the auxiliary contact carrier which in case, for instance upon a drop out of the spring acting upon the auxiliary contact carrier can lead to an uncontrolled movement of the auxiliary contact carrier.